Erikson (1950) contends that the physical changes associated with puberty serve as a catalyst for adolescents to question childhood identifications and to consolidate these with current self-conceptions, personal ideologies, interpersonal values, and future aspirations. Erikson describes the adolescent identity crisis as the developmental period when identity development becomes salient. For males, pubertal changes have implications for sexual identity development and self-perceptions of masculinity, which are aspects of the identity exploration and integration process that occurs during adolescence. This study is an examination of the impact of age, grade, and physical development on male identity development. A purposive sample of 173 Anglo-American male participants in Grades 6 through 12 completed the Petersen Development Scale and The Extended Objective Measure of Ego Identity Status (EOM-EIS) in their homes. Statistical analyses revealed that physical development shared more variability (20% explained) with the identity measure than either age (8.3%) or grade (4.2%). Advanced physical development correlates with lower Foreclosure scores and higher Moratorium and Achievement scores. These findings are consistent with Erikson's life span theory of psychosocial development.